In BIG-IP LTM, a pool member state directly affects how traffic is handled at the data plane level. When a pool member is manually disabled , BIG-IP changes the member’s availability state to disabled , which has specific and predictable traffic-handling consequences.

According to BIG-IP Administration Data Plane Concepts:

A disabled pool member :

Does not accept new connections

Continues to process existing non-persistent connections until they naturally close

Is removed from load-balancing decisions , including persistence lookups

Most importantly for this question:

Persistent connections (such as those created using source-address persistence, cookie persistence, or SSL persistence) are not honored for a disabled pool member

BIG-IP will not send new persistent traffic to a disabled member, even if persistence records exist

Therefore, when a pool member is manually disabled, it stops processing persistent connections , while allowing existing non-persistent flows to drain gracefully.

Why the Other Options Are Incorrect:

B – Persistent connections are not honored for a disabled pool member

C – Existing connections are not immediately terminated when a pool member is disabled

D – Only the disabled pool member stops accepting new connections, not all pool members

Key Data Plane Concept Reinforced:

Manually disabling a pool member is a graceful administrative action that prevents new and persistent traffic from reaching the member while allowing existing connections to complete, which is critical for maintenance and troubleshooting scenarios.

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